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# Tag Info

148

This is an interesting question, but it lacks a key factor that is crucial to the answer: TIME. The point on Earth closest to the Sun varies through time, so the question can be asked about any moment in time, or over periods of time. Let's analyze the factors involved. At any given moment in time, the point on Earth's surface that is closest to the Sun is ...

12

Short answer. When the Earth is closest to the sun in January that softens the seasonal variation in the Northern Hemisphere and it increases the seasonal variation in the Southern Hemisphere, so for now, in the Northern Hemisphere, the Summers are colder than they would be with a circular orbit and the winters are hotter. The opposite is true in the ...

10

In short: No. Unless multi-million timescales are considered. The reason we keep teaching Newtonian mechanics, is because it is a VERY accurate approximation of a more general theory (general relativity) within the regimes of speed and gravity acceleration found in everyday life. Therefore, all the relativistic corrections to Newtonian mechanics in the ...

10

It is impossible to know. Solar flares can have more than 500,000 kilometers. So if we consider them part of the sun, the moment when the earth is closer to the sun can be very different from perihelion if a big flare happens, making much of what was discussed in other answers irrelevant.

6

The ecliptic path, is a well defined trajectory when displayed on the background of the fix stars like in the following figure (taken from physics.csbsju.edu) However, there is not such thing as an ecliptic path on the surface of the Earth. If you thought of it as the "Ground track" of a satellite but applied for the Sun, you have to consider that the ...

5

Yes, but this is not mainly due to the small intensity variation of sunlight with distance. Rather, the elliptical orbit affects the length of the seasons, which — along with other orbital effects — triggers the ice ages. Currently, in the northern hemisphere, summers are longer than winters, because of Kepler's orbit laws and the fact that perihelion is ...

5

What is the Moon's distance from viewer at horizon? As noted by others, the moon follows an elliptical orbit, which will lead to the greatest change in distance regardless of the observation angle. However, we can place some upper and lower bounds on what the distance at the horizon would be by using the maximum and minimum orbital radii (the apogee and ...

4

The point on the surface of the Earth where the Sun is currently immediately overhead is called the Zenith Point. Its Latitude and Longitude correspond to the Declination and Greenwich Hour Angle of the Sun. These data points can be approximated to any degree of accuracy and timeframe by a Fourier series of n terms. Accuracy sufficient for sextant work ...

4

The Moon's orbit is elliptical, not circular, and the maximum and minimum distance from the Moon to the center of the Earth (apogee and perigee, 405,385 and 363,630 km respectively) are much larger than the radius of the Earth (6370 km). Therefore, the distance you are asking for is very variable and it does not depend so much on the position of the Moon ...

4

The tidal effect over time tends to circularize orbits. It's well known that Moon is being tidally pushed away from the Earth over time (about 1.5 inches a year). This effect is stronger when the moon is closer and weaker when the moon is farther, so there is a very gradual tidal circularizing of orbits over time, unless the orbit is highly eccentric, ...

3

This doesn't answer your question entirely, but if by "sun-earth radius" you mean the distance between the Earth and the Sun, you can visit https://ssd.jpl.nasa.gov/?horizons with these settings: to see that the length of the Earth's semimajor axis (the "A" value in each row) doesn't change much over the years (it remains very close to 1 AU, as expected). ...

3

What is usually shown in cyclic plots showing precession is the precession index ($e \cdot \sin\varpi$ where $e$ is the eccentricity and $\varpi$ is the moving longitude of the perihelion). It is dimensionless ($e$ and $\sin \varpi$ being ratios). Here is the precession index for the last 2 Myrs that I plotted using data from Laskar et al. (2004) (in the ...

3

I don't see this point made, so I'll just add it. In very high gravitation situations orbital energy can be lost to "relativity" or more specifically, gravity waves. The primary relativistic effect that the Sun's gravity has on Mercury is an increase in it's precession, as @CamiloRada pointed out, and see more details here. A secondary relativistic ...

3

The latest positions that I am aware of say yes, but not in any useful way. From what I have read, the current prevailing opinion is that the weather of Earth is a chaotic system. Chaotic systems are known to be very sensitive to initial conditions. Eddys in the atmosphere that are mere milimeters in size may change whether it rains or shines on the other ...

2

Something that I noticed in your formula is that you are using 365 for the amount of days in a year. Perhaps trying it using 365.25 would be more correct as it accounts for the leap year. Please let me know if this helps/corrects the issue.

2

Whichever spot on the surface of the Earth is experiencing Lahaina Noon, or would be if it wasn't cloudy, is at the subsolar point and pointed directly at the Sun, moreso than any other point on Earth at that moment. Of course, you could get closer to the sun by climbing higher. If you were able to be at the summit of Chimborazo volcano in Ecuador (point ...

2

There are some wonderful answers here, but I think a simplified plain English answer would be helpful. Barring any nearby mountains, and various foibles, the closest point to the sun at the June solstice is where it is midday on the tropic of Cancer. At the December solstice, it is where it is midday on the tropic of Capricorn. At equinox it is where it is ...

1

At any one specific moment the subsolar point is the point on Earth that is closest to the Sun at that specific moment. The subsolar point on a planet is the point at which its sun is perceived to be directly overhead (at the zenith); that is, where the sun's rays strike the planet exactly perpendicular to its surface. It can also mean the point ...

1

No. There is a difference in daylight according to latitude, but it is not because of proximity to the sun, and nor is there a significant difference in the total number of daylight hours in a year. What is different is that at the equator, the length of the day is nearly equal all year round. The higher your latitude (the further from the equator and the ...

1

The Earth's equator is about 0.006% closer to the sun than the Earth's mean spin axis, so the effect of proximity to the sun on daylight hours is so small that my calculator - which has a register of 10 significant figures - can't even discern any difference. A rough back of an envelope hand calculation indicates less than a millionth of a second difference ...

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